Field of the Invention
The present invention relates to a technique of determining a deterioration state of a battery with a high degree of accuracy.
Description of the Background Art
A technique of determining whether a battery can be reused or not based on a deterioration state of the battery is known. As the technique of determining the deterioration state of the battery, Japanese Patent Laying-Open No. 2012-127938, for example, discloses a technique of calculating a degree of deterioration of a power storage device with respect to a calendar life or cycle life, based on the number of cycle damages based on a charging current value, a charging time and a representative temperature of the power storage device.
In a sealed battery, a component such as a resin member, a gas discharge valve or a CID (Current Interrupt Device) is, for example, used to maintain a sealed state. Due to fluctuations in internal pressure of the battery depending on age deterioration, usage conditions and the like, fatigue may be accumulated and deterioration may progress in these components. Therefore, in order to determine the deterioration state of the battery with a higher degree of accuracy, the fluctuations in internal pressure of the battery must also be taken into consideration.